1. Field of the Invention
The present invention relates to rear projection visualization systems and in particular to a construction which minimizes the visual seam between adjacent screens of a rear projection visualization system.
2. Description of the Prior Art
In numerous industries, rear projection visualization systems have become important visualization and design tools. In such systems, the image is projected from the rear side of a translucent screen, relative to the location of the viewer. This allows the viewer to move as needed in front of the screen without interfering with the projected image and without interfering with the viewer's perception of the projected image. In some situations, more than one screen may be used to display a large melded image because such a single screen would be too large to manufacture in one piece. Other applications, such as screens for more immersive virtual reality systems, require multiple adjacent screens as the images are melded together from multiple projectors to create the desired effects. These systems exhibit enhanced immersiveness when the screens are at angles relative to one another, completely or partially surrounding the viewer.
When melded multiple images are back projected onto two adjacent screens, particularly when those screens are at angles relative to one another, a dark, finite width, "visual seam" is created between the two screens. The darkness in the visual seam is caused by the frames supporting the screens. These frames prevent light, from the projectors, from reaching into the space where the screens meet. The melded images which cross over the two screens are thus interrupted by a dark visual seam which runs the height of the screens. In some constructions, the ends of the screens are bent or radiused around the frames and the frames prevent projected light from entering into these radiuses.
Generally illustrative prior art systems include U.S. Pat. Nos. 5,103,339; 5,400,178; and 5,206,760.
A multi-panel framing system is disclosed in U.S. Pat. No. 5,103,339. The edges of the screens are compressed and fastened between brackets in the front and rear of the screens. While holding the multiple screens securely together, portions of the brackets are visible in the front of the screens leaving a visual seam between the screens.
An alternative approach to join multiple screens and minimize the visual seam is disclosed in U.S. Pat. No. 5,400,178. Here multiple screen panels are adjoined in a lattice framework where the square lattice of screens is installed in an outer frame. While the disclosed structure may minimize the visual seam, it can only be used for a uniformly flat screen. Some applications, such as those for virtual reality systems, require adjacent screens to be angled at less than 180.degree. from each other.
A further alternative approach is disclosed in U.S. Pat. No. 5,206,760 where multiple screens are adjoined with a transparent bracket. The bracket is H-shaped and decreases the missing information in the dark visual seam area by using the bracket as a lens. Similarly to U. S. Pat. No. 5,400,178 described above, this approach can also only be used with screens angled 180.degree. next to each other.
In view of the foregoing limitations and shortcomings of the prior art devices, as well as other disadvantages not specifically mentioned above, it should be apparent that there still exists a need in the art for a construction that minimizes the visual seam between adjacent screens.
It is therefore a primary object of this invention to fulfill that need by providing a construction which reduces the average perceived width of the visual seam between two screens which are at an angle less than 180.degree. relative to each other and to have the visual seam illuminated by channeling light from the projector through a translucent material into the seam.